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On its journey, MMS will observe a little-understood, but universal phenomenon called magnetic reconnection, responsible for dramatic re-shaping of the magnetic environment near Earth, often sending intense amounts of energy and fast-moving particles off in a new direction. Not only is this a fundamental physical process that occurs throughout the universe, it is also one of the drivers of space weather events at Earth. To truly understanding the process, requires four identical spacecraft to track how such reconnection events move across and through any given space in 3D.
Launching four satellites into space simultaneously is a complicated process. In addition, each spacecraft has six booms that will unfold and extend in space once in orbit. A launch and deployment with so many moving parts must be meticulously planned.
Watch the video to get a sneak preview of how MMS will make this journey: The four spacecraft are housed in a single rocket on their trip into space. One by one, each ejects out, before moving into a giant pyramid-shaped configuration. Next each spacecraft deploys its six booms.
Once in orbit, MMS will fly through regions near Earth where this little-understood process of magnetic reconnection occurs. Magnetic reconnection happens in thin layers just miles thick, but can tap into enough power at times to create gigantic explosions many times the size of Earth.
Reconnection happens when magnetic field lines explosively realign and release massive bursts of energy, while hurling particles out at nearly the speed of light in all directions. Magnetic reconnection powers eruptions on the sun and – closer to home – triggers the flow of material and energy from interplanetary space into near-Earth space. The MMS orbit will carry the four spacecraft through reconnection regions near Earth, using this nearby natural laboratory to better understand how reconnection occurs everywhere in space.
For more information about MMS, visit: www.nasa.gov/mms
Learn more about MMS at www.nasa.gov/mms
Trying to understand how gigantic explosions on the sun can create space weather effects involves tracking energy from the original event all the way to Earth. It's not unlike keeping tabs on a character in a play with many costume changes, because the energy changes form frequently along its journey: magnetic energy causes eruptions that lead to kinetic energy as particles hurtle away, or thermal energy as the particles heat up. Near Earth, the energy can change through all these various forms once again.
Most of the large and small features of substorms take place largely in the portion of Earth's magnetic environment called the magnetotail. Earth sits inside a large magnetic bubble called the magnetosphere. As Earth orbits around the sun, the solar wind from the sun streams past the bubble, stretching it outward into a teardrop. The magnetotail is the long point of the teardrop trailing out to more than 1 million miles on the night side of Earth. The moon orbits Earth much closer, some 240,000 miles away, crossing in and out of the magnetotail.
Magnetic reconnection happens when magnetic field lines come together, break apart, and then exchange partners, snapping into new positions and releasing a jolt of magnetic energy. This process lies at the heart of giant explosions on the sun such as solar flares and coronal mass ejections, which can fling radiation and particles across the solar system.
Magnetic field lines, themselves, are invisible, but the sun's charged plasma particles course along their length. Space telescopes can see that material appearing as bright lines looping and arcing through the sun’s atmosphere, and so map out the presence of magnetic field lines.
Looking at a series of images from the Solar Dynamics Observatory (SDO), scientists saw two bundles of field lines move toward each other, meet briefly to form what appeared to be an “X” and then shoot apart with one set of lines and its attendant particles leaping into space and one set falling back down onto the sun.
To confirm what they were seeing, the scientists turned to a second NASA spacecraft, the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). RHESSI collects spectrograms, a kind of data that can show where exceptionally hot material is present in any given event on the sun. RHESSI showed hot pockets of solar material forming above and below the reconnection point, an established signature of such an event. By combining the SDO and RHESSI data, the scientists were able to describe the process of what they were seeing, largely confirming previous models and theories, while revealing new, three-dimensional aspects of the process.